1. The refresh rate (which is not the resolution."
2. The Monitor.inf file used. While it's not a driver, it tells Windows and the video driver how to deal with the display. This may be called a monitor driver, or it may be called an info file. Some folk get stuck on this but let's plow through.
3. Some displays have settings. My Sony has this FULL PIXEL setting, A Samsung calls it "Just Fit" and you get the idea I will never guess what your display calls it.

So I can't fix this for most people. But these 3 areas need to be under control and understood by your support person.